In my opinion the most important part of internet marketing is to define your target audience. Then use as much sources as you can to reach it! I'm prefer to start with social media, such as fb, twitter, and instagram.
Yes, as most people are in the social media. They spent their hours even their day browsing thru their phones.
It's the easy way to reach your target audience. Like just one click you can reach them and tell what your up to.
Your topic must be applicable to your target market of course.